This article requires editing of the key SSH file configurations. You can use any text editor you like, but. In this case we’ll use nano, the Linux Nano text editor.

When you’re in a position to begin, be sure to follow the next steps.

Step 1: Change your directory to /etc/ssh/ via the below command

cd /etc/ssh/

Step 2: Here, you need to make a backup of your current sshd_config for security side. To do this, run the below command

cp sshd_config sshd_config.bak

Step 3: You’ll now need to edit the sshd_config file using the below command

nano sshd_config

Step 4: In nano, search for the word “port” by using ctrl+w

Step 5: Once you able to locate the port setting, you can delete the # symbol to uncomment the line

Step 6: Change the port number, which should be 22, to any port you wish under eg 1981

Step 7: It is advised not to use the below ports as they are generally in use for the different services

25
53
110
443
495
21
80
2083
2082
2086
2087
2096
9876

You can always use command cat /etc/services to find which port numbers are configured on your server

Step 8: Finally restart the SSH service with the following command and changes will get applied.

service sshd restart

Thank you.

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It is a great tool/command for synchronizing files and directories. (Remote Sync) is an extremely versatile tool that can be used to copy and synchronize directories and files in remote or local environments. Learning this command will assist you to efficiently transfer information across multiple servers, or create backups to restore. The reason it is so effective is the variety of options that allow control over the behavior of the command, which allows you to adjust to your specific requirements.

It also employs an algorithm known as the “delta-transfer algorithm” that reduces the amount of bandwidth that is transferred through the network by passing the difference between source and destination files. We will cover only a handful of instances in this post, which will hopefully help you understand the basics of this command-line software and help you achieve your objectives.

The most fundamental syntax of the command is

rsync <option> <source> <destination>

Copy files/directories in a local environment

With rsync, you are able to quickly make backups of your website by copying the website’s files from its root directory into a folder specifically designated to store backups. If you are using a cPanel-based server, the domain name’s primary files are stored in the “public_html” directory inside the home directory for the individual user. Backups are saved within the “/backup” global directory.

Here is the rsync command you can use

rsync -aHvz /home/username/public_html/ /backup/website-backup 

• a – use this option in the command is going to enable “archive mode”. The archive mode preserves all file ownerships, permissions, and modification times of files and folders.
• H – use of this option is going to preserve hard links.
• v – use of this is going to provide more information while the sync is ongoing.
• z – use this option is going to compress the transferred data, reducing the amount of bandwidth transmitted.

Copy files/directories in a remote environment

Let’s try the previous example However, let’s make use of an external server we can transfer the backup

rsync -aHvz /home/username/public_html/ user@backupnoc:/backups/website-backup

In default rsync will make use of the OpenSSH process to share files since it’s the most secure method. There are occasions when service providers modify their SSH ports due to security concerns. If this happens, rsync provides an option to determine that port as the one to be changed.

Here’s how the command will appear like

rsync -e "ssh -p " -aHvz /home/username/public_html/ user@backupnoc:/backup/website-backup 

The “-e” flag allows you to set the SSH service’s customized port. This command is able to work in the reverse direction, permitting you to transfer documents from the server and transfer them to locally hosted servers. It is possible to pull files from the remote server “pull” process is also often referred to as an “reverse rsync”, and it is a way to restore an earlier version of your site. This is what it looks like:

rsync -aHvz user@backupserver:/backup/website-backup/ /home/username/public_html/

An additional utility of the rsync command

Do you realize that rsync can be used to erase files, too? It’s one of the fastest, if not the most efficient methods to accomplish this, particularly when you have lots of files that require an enormous amount storage space on your disk. In order to use this method it is necessary to create a blank directory. It doesn’t matter what the name is in this scenario. The crucial thing is that it remains empty. Finally, you need to use the following command:

rsync -a --delete name-of-empty-folder/ name-of-folder-you-want-to-delete/

What rsync will be doing is creating a synchronization between the empty directory and the complete one, basically not syncing anything with anything that will remove all files in the directory that are populated. Be very careful while doing this, because the process is irreversible and absent a backup, you’re unlikely to retrieve your information.

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How to Access Remote Server or Terminal :

To start for the command line, make sure that you have access to a remote server or shell prompt. Also, one can demand ssh enable through chat or ticket if you own shared, reseller or vps hosting with Hostpoco. You can then find an option named Terminal under hosting cpanel, where you can use these basic commands.

SSH stands for Secure Shell, it’s a type of protocol used to securely connect to a remote server/system.

Steps to access your remote server:

There are two well-known and recommended methods to make ssh connection. Using an SSH client like Putty. It requires you to enter the server’s IP and the port number into the corresponding fields.

Using Terminal Shell: This is the option available under hosting Cpanel which you will be able to see once your hosting provider enables ssh access for your account.

You will need to write details under the destination section of putty along with the port number:

ssh user@serverip or hostname

Remember to replace ssh “root” with your real username and ssh “192.168.1.1” with your server’s dedicated or shared IP address.

Make sure that you have filled the correct details and then click on open. Once you click the Open button on PuTTY or the accessed the terminal option under Cpanel, you will be prompted for a user/shell password. If you are making ssh connection first time on the server then you might get a warning message, telling you that the server is not recognized. Just click on Yes to continue.

Done. Now you’re connected to the server and can start executing SSH commands from your end.

List of Basic SSH Commands

Now we will go through popular SSH commands and learn about using them.

Here is the quick look of the basic SSH commands which we will cover.

ls command

This command is useful to list the contents available under the directory

Also available the below options to get more info

-l : ls -l displays the details of the files, such as size, modified date and time, the owner, and the permissions.
-a : ls -a shows hidden files and directories

cd command

cd (Change Directory) is the command that use to jump between directories. This is a simple command, just type cd followed by the name of the directory:

cd [directory]
eg : cd home , cd testdirectory

To go back one level reverse, you can simply enter “..” (two dots) after cd command:

cd ../..
Enter this command to get in-home directory again.

mkdir command

This command is useful to create new directory

mkdir [folder name]
Assume that you want to create a new folder named “mydata”. You will need to type:

mkdir mydata

touch command

one can easily create new file using this command, it can be with extension or without extension. It can create files without any extension too

touch [file name]
If you want to create a .txt file named “testfile”, this is what you need to write:

touch testfile.txt.

rm command

rm command helps to remove a chosen file or directory. To delete a file, enter:

rm [file name]
For instance, if you want to remove testfile.txt, simply execute:

rm testfile.txt
To delete a directory, you need to use the -r (recursive)option to remove all the files and subfolders inside it:

rm -r home3/hostpoco/mydat

cat command

This command is very useful to view contents from the file

cat [file name]
This also allows you to create a new file by merging multiple files. Eg:

cat info.txt info2.txt > infomerge.txt
This execution will help to merge the content of info.txt and info2.txt into infomerge.txt

pwd command

pwd is a command that prints the full path of your working directory. Eg:

home/user/public_html
It’s handy if you want to get the exact path in case you need to update your provider for some work

cp command

This ssh type of command is helpful to copy files and folders.

cp [options] [source] [destination]
[source] should be the file or folder you want to copy and [destination] is the duplicate.

Let’s assume that you have mydata.txt in your working directory, and you want to make a copy of it. It should work like below way:

cp mydata.txt mydata2.txt
Also if you want to make a copy in a different folder, run the below command:

cp /home/hostpoco/mydata.txt /home/testuser

mv command

This command works in a similar way to cp. However, mv command will move the file or folder instead of copying it. This is the syntax:

mv [source] [destination]

grep command

grep command is for searching purposes, looks for a given string in files. For example:

grep ‘line’ info.txt
The above command would search for ‘line’ in a file named “info.txt”.

find command

This command is useful to search for a file/files that meet with the format (name, size, file type, etc). The basic syntax is as below:

find [starting directory] [options] [search term]
[starting directory] is where you would like to start your search process. There are three main choices:

/ (slash) — search the whole system
. (dot) — search the working directory
~ (tilde) — search the home directory
Additional arguments :

-name — look for files based on their names
-user — search for files that belong to a given user
-size — look for files based on their sizes
[search term] is the keyword or number that you use to search for files.

Take a look at this example:

find . -name “index”
This command will return any files that have the word “index” on their names. And since we use “.” (dot), the command will only search the working directory.

vi/nano command

Vi and Nano are the popular text editors from where you can view, modify your files. You can simply fire the below type of command if you wish to modify any file:

vi [yourfilename]
or

nano [yourfilename]

chmod command

This command type is use to change the permission of file or folder. Generally its not useful for shared hosting but useful in case you have vps or dedicated server. Eg :

chmod 644 filename ; chmod 755 filename

here 644 mean read and write access
and 755 read, write and executable access

chown command

This command is use to change ownership of file or directory. This also mostly used on vps or dedicated server only

zip command

This command is used to make zip file of the contents or directories. eg :

zip -r directoryname.zip directoryname

unzip command

This command is used to unzip any zip file and syntax should be as below :

unzip directoryname.zip

mysqldump command

This command is useful to generate backup of your database

mysqldump -h [SERVER] -u [USER NAME] -p [DATABAS]> dumpfil.sql

This result into exports of your database and saves it as “dumpfil.sql”. The brief of arguments used in above command are as below :

-h : hostname of database server
-u : username of database user
-p : password of database

history Command

This command is useful to display the last used commands. You can enter a number to limit the displayed results. eg:

history 10
This will show you the last 10 used commands

clear command

This command helps to clears all text from the terminal screen

tar Command

tar is a famous SSH command that creates or extracts .tar.gz files. It is very popular because most third-party software binaries are in the .tar.gz format also best options for backup creation and extraction

To compress a folder in .tar.gz format, use the below command:

tar cvzf archivedfile.tar.gz /path/to/directory
To uncompress a .tar.gz file, enter this command:

tar xvzf archivedfile.tar.gz
The both above commands use different four-character options — cvzf and xvzf. Each letter represents a specific instruction as below:

x used to extract files
c used to create an archive
v stands for verbose.. use to display all file names that are processed by the command.
z used to uncompress the archive file
f use to define name of the archive

wget command

This is the command used to download files from the internet. For example, you wish to fetch downloadable backup from the website then you can use below syntax

wget http://yourfileurl/sitebackup.tar

If you want to download multiple files then you need to put URLs into a file and use the -i option.

du command

You can use du ie disk usage command to view exact size of files, directories and more info

du [folder path]

In most of the cases vps and dedicated server always have shell access but not for shared hosting. Limited hosting providers are offering shell or terminal access, you can try Hostpoco hosting services if you wish to get shell access.

Summary

Getting familiar with ssh commands is a crucial task but essential for managing Linux server, vps or hosting. It is the most effective way to navigate through your system and modify files or directories.

Glad to see, that you have learned about basic ssh commands. Its useful for handling your server related tasks. Please contact us for more queries.

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